Web Platform APIs

What you'll learn

• Fetch in depth — requests, responses, headers, error handling
• AbortController as the standard cancellation primitive
• URL and URLSearchParams for safe query strings
• The History API and the bones of client-side routing
• Storage choices — localStorage, sessionStorage, and IndexedDB
• Streams and large responses without filling memory
• Real-time messaging with WebSockets and Server-Sent Events
• Observers (intersection, resize, mutation) and Web Workers

1. 01
   fetch in depth

   Requests, responses, headers, JSON vs text vs blob, and the error handling that nobody tells you about.
   16 min
2. 02
   AbortController and cancellation

   One signal cancels them all — fetch, listeners, observers, timers.
   13 min
3. 03
   URLs and search params

   Building query strings without bugs. URL, URLSearchParams, and the encoding traps.
   13 min
4. 04
   The History API

   pushState, replaceState, popstate — client-side routing in fifty lines.
   14 min
5. 05
   Storage

   localStorage, sessionStorage, cookies — quotas, JSON-in-a-string, and what each one is actually for.
   13 min
6. 06
   IndexedDB

   When localStorage runs out. The object-store model, in plain words.
   17 min
7. 07
   Streams and large responses

   ReadableStream and fetch streaming — when streaming earns its keep.
   15 min
8. 08
   Real-time: WebSockets

   Two-way messaging, lifecycle, and reconnect patterns.
   15 min
9. 09
   Real-time: Server-Sent Events

   When SSE beats WebSockets. EventSource, retry semantics, and the simpler half of real-time.
   12 min
10. 10
    Observers and workers

    IntersectionObserver, ResizeObserver, MutationObserver, and Web Workers in one lesson.
    17 min